The Botanic Matchmakers that Could Save Our Food Supply

Walk through the New York Botanical Garden in the Bronx, past the exotic orchids, blossoming bougainvillea, swaying grasses and a patch of pristine forest like the one that was here when the Dutch arrived in the 17th century, and you’ll likely miss the most significant plants in the place. Scattered amidst the displays of boisterous and fragrant vegetation, in one of the most celebrated plant collections in North America, are the wild relatives of our most important food crops.

In their untamed form, they’re barely recognizable as in the same family as the fruits and vegetables on our dinner plates. But there they are—the crenellated leaves with little yellow flowers in the genus of Brassica, progenitor of broccoli, bok choy, brussel sprouts, turnips and cabbage; the fernlike leaves of the Juglans genus of walnuts, pecans and hickory nuts; and even a couple of short, wild banana trees. They may not look familiar, but scientists are discovering that many of them have characteristics that are critical to the survival of crops facing the tumultuous shifts in growing conditions triggered by climate change. Only a fraction of the wild relatives of food crops have been collected in any systematic way, but the hunt is on for them as plant scientists come to understand the important reservoirs of genes they possess from the mere fact of having survived so many seasons of changing conditions.

Many of us humans have cousins or aunts or uncles who may not conform with the rest of the family, who embarked on a different path, and yet are part of our family’s fabric—our “wild relatives.” The same thing exists in the world of plants. From the grasslands of the Midwest to the Eastern seaboard, from the mountains of Central Asia and Mexico to the dry gulches of Arizona come the undomesticated family members of the plants we have tamed as food. But they remain wild, out there growing on their own, evolved to ecosystems that may be far away from the fields where their domesticated cousins are cultivated to feed us. They haven’t been propped up with pesticides or weaned on fertilizers. They have adapted.

In many Indigenous communities, farmers encourage their growth along the borders of their farms to foster cross-fertilization between their crops and these hardy varieties. But most industrial agriculture treats them as more like unwanted weeds.  That is a mistake, says Alex McAlvay, who runs the NYBG’s crop wild relatives program.

“With the industrialization and homogenization of the food system we have lost many of the characteristics that come from crop diversity,” he said. “Climate change drives home the importance of preserving wild landscapes, because they harbor plants important to our food security.”

McAlvay led a research team last year that identified the Hindu Kush mountain range, stretching across Pakistan, Afghanistan and Tajikistan, as the source pool of diversity for the Brassica rapa crops, those relatives of napa cabbage, turnips and bok choy  now growing in the New York garden. The research, published in the peer-reviewed journal Molecular Biology and Evolution concluded that conserving those varieties was critical “to cope with changing environmental conditions” in the future.

Searching for a wild bean in the desert washes of Southern California. Credit: Colin Khoury
Searching for a wild bean in the desert washes of Southern California. Credit: Joe DeWolf/San Diego Botanic Garden

“The real advantage of these relatives is to help with the extreme events that are being aggravated by climate change,” he said. “Resisting drought, flooding, extreme weather events, these are traits that wild relatives tend to shine in and have leveraged to maximum effect.”

A couple of examples: a cousin of wheat, called Aegilops tauschii, growing wild from Syria and the Middle East to the Caucusus—the so-called Fertile Crescent—have bolstered resistance to a fruit fly that’s followed the warming temperatures into the wheat fields of the American Midwest. And the progenitor cousin of corn, teosinte, growing wild in the mountains north of Oaxaca, Mexico, has repeatedly contributed to the breeding of commercial corn varieties resistant to the corn borer and other pests. A study in Crop Science lists multiple commercialized crops that have benefited over the years from breeding with their wild relatives, including barley, bananas, chickpeas, corn, hops and wheat.

wild wheat illustration
Credit: Paul Horn

But three-quarters of the crop seed varieties on Earth in 1900 were extinct by 2015, and the U.N.’s Food and Agriculture Organization predicts we are on the verge of losing as much as a third of the 400,000 remaining varieties. In North America, a recent study in PNAS identified at least half of the ‘wild relative’ populations in North America as threatened with extinction driven by climatic changes and other pressures. That includes relatives of the apple, plum, blueberry, pecan, walnut, potatoes, wheat, corn and numerous beans, many of which contain characteristics that could prove critical to the survival of crops facing their own tumultuous shifts in growing conditions. Such stats have triggered alarm in the cloistered world of botanic gardens, institutions known mostly for their blissful detachment from the outside world.

“There are winners and losers in the process of domestication,” said Colin Khoury, senior director of science and conservation at the San Diego Botanic Garden and lead author of the PNAS paper. “Many of those ‘losers’ contain the key to resistance to climate threats.”

After a century of rapid-fire plant extinctions, and on the verge of losing more, Khoury and McAlvay are among a new generation of plant scientists focused on expanding the role of botanic gardens into conserving the relatives of common food crops, which they see as critical to a stable food supply as climate change wreaks havoc with agriculture. The effort involves an unprecedented level of cooperation between gardens and a novel approach to conservation—a dating service for crop wild relatives to ensure their genetic diversity.

A Global Alliance of Gardens                                              

Plants experience climate change as a rewiring of ecological cues. When the temperature rises and the winter comes even a week or two later, as is the case in many parts of the Midwest, bugs have longer to feast on crops. When it doesn’t get cold enough in winter, as has been the case recently in California’s Central Valley, tree-fruits don’t fully develop. After freak torrents of rain during warm weather, fungi have a field day in moist, warm fields.

In evolutionary terms, these volatile shifts are happening at a rapid and accelerating pace. The botanic gardens are starting to look for and identify the ways in which wild relatives survive such climatic changes and what that portends for breeding with their commercialized, edible cousins. The process of domestication often excludes such “survival” characteristics in favor of taste, shape or other traits perceived as central to the commercial success of foods. Many relatives of cultivated plants were displaced by the monocrop seeds that dominate North America and much of the world. And those cultivated crops are now incapable of adapting to changing ecosystems and are dependent on chemical fertilizers and pesticides to thrive.

Jamal Mabrouki works at a grasspea breeding facility at Marchouch Station, Morocco. Credit: Michael Major/Crop Trust
Jamal Mabrouki works at a grasspea breeding facility at Marchouch Station, Morocco. Credit: Michael Major/Crop Trust

But those wild relatives that did survive, did so without human assistance. They adapted, one of the most critical characteristics in this time of high volatility. And because they’re related, they don’t require genetic engineering to pass on traits; they can reproduce them naturally. Growers of wine grapes in California have relied for years on cross-breeding with wild relatives of the grape to provide resistance against phylloxera pests that feed on the roots and leaves of grapevines, which are more vulnerable when weakened, scientists have found, by drought conditions.

Botanists can “read” the seeds and stalks of wild relatives, and, like the stories embedded in the rings of a tree, discern the conditions when they took root, and the stress factors they faced as they grew. Chris Pires, former chief science officer for the New York Botanical Garden, described their herbarium as “like a time machine,” offering insights into past climatic and other challenges that plants are capable of surviving.

Since November, some two dozen botanic gardens in North America have started sharing the details of their holdings for the first time, an effort to inventory how much backup exists for threatened populations of crop wild relatives. Over the past nine months, Khoury and his colleague Abby Meyer, executive director for North America of Botanic Gardens Conservation International (BGCI), convened a series of Zoom meetings between two groups specializing in the wild relatives of tree-fruit and nut crops. 

One after another, officials from gardens in St. Louis, Atlanta, San Diego, Minneapolis, Berkeley, Toronto, Vancouver and elsewhere shared what they have in their collection, and what they perceive to be missing. It was a blur of Latinate names, which took a quick visit to Google to translate—the Prunus (the family of cherry and almond—yes, they’re related), the Diospyros (family to the persimmon), the Malus (apple family), Corylus (hazelnut family) the Juglans (walnut family) and many more.

Each participating garden in the network, including the New York garden, is asked to contribute the characteristics of the wild relatives in their collection to a collective database, the first step in determining which populations are the most inbred and in need of genetic outbreeding. With that metadata, Meyer explained, they are laying the ground for gardens to exchange grafts and seeds in a continent-wide effort to ensure the most genetically diverse, and thus resilient, populations of wild relatives of food crops.

The BGCI was founded by London’s Kew Gardens in 1987 to coordinate global plant conservation. Since then, climate change has raised the stakes, Meyer says. 

“We come from the place of trying to demonstrate to our public that climate change is a real thing,” she says. “Recently, our conversations have shifted to, ‘OK, this is the future climate we’re going to be in. It’s going to get hotter, drier, here. It might get wetter and more extreme somewhere else.’ Gardens are saying, ‘This is our future,’ and asking, ‘How do we exist in our future?’”

Trevor Rowe measuring the plant height of alfalfa at the Waite Institute, Adelaide, South Australia. Credit: Michael Major for Crop Trust
Trevor Rowe measuring the plant height of alfalfa at the Waite Institute, Adelaide, South Australia. Credit: Michael Major/Crop Trust

Meyer was a co-author of a recent paper in Conservation Biology outlining what the plant world could learn from a National Zoo initiative to diversify the genetic population of captive mammals, particularly those whose wild populations are endangered. Zoos around the world maintain ‘stud books’ for the world’s most endangered mammals. Representatives of species in danger of inbreeding within a captive population get sent to the Smithsonian Institution’s Conservation Biology Institute in the Blue Ridge Mountains of Virginia for a visit with a mate provided by a different zoo in hopes that they reproduce and diversify the gene pool. (At any given time, the hills of the 3,200-acre facility abound with exotic mammals of every variety, including oryxes, zebras, gazelles, pandas and Przewalksi horses).

The botanic gardens initiative aims for something similar, but with plants. The first step is identifying the wild relatives and existing populations, determining the most vulnerable or inbred and then knowing where to send them to breed them out to replenish the gene pool. In 2020, the Chicago Botanic Garden received a $731,000 grant from the Institute of Museum and Library Services to devise software that will facilitate exchanges between the botanic gardens. They’re getting close to completing that three-year project. “It’s Eharmony for trees and plants,” Meyer said, chuckling.

Modern Botanical Collaborations Grow From Century-Old Roots

In the 1920s, Russian botanist Nikolai Vavilov first identified the centers of plant biodiversity in western scientific terms. On forays to every inhabited continent he theorized that the source pools of genetic variation from which emerged the cultivated varieties that end up on our dinner tables are centered in a band around the equator, stretching from central Asia to the Middle East to Latin America and central Africa, mostly in developing countries and often on land inhabited by native communities.

wild rice illustration
Credit: Paul Horn

Vavilov was interested in what could help strengthen the resilience of Russian agriculture to the country’s harsh conditions, but his findings linking the evolved characteristics in the wild to cultivated varieties in farm fields rippled around the world. His work was so cutting edge that for several years in the 1920s, the American USDA gave him an office to work out of in New York City, where he collaborated and exchanged plant materials with American plant scientists—a rare instance of U.S.-Soviet partnership shortly after the Russian Revolution.

At the time, few envisioned the tumultuous climate disruptions that would come a century later. But the resources identified by Vavilov, and the many farmers and scientists who followed in his wake, turned out to be critical to the survival of modern-day agriculture, made highly vulnerable by its homogeneity and reliance on agri-chemicals to survive. The increasingly urgent search for what the U.N. refers to as genetic resources is setting up a potential clash between the conservation interests of botanic gardens, claims by Indigenous communities to the cultural and agricultural knowledge linked to the plants in their territories and the commercial interests of major seed companies.

As the value of food crops’ wild relatives to agriculture increases—their potential contribution to global yields is valued at $115 billion to $120 billion annually, according to Botanic Gardens Conservation International—the tensions over accessing them in their remote habitats and bringing their genetic advantages to the developed world, and the protocols that govern that process, will only increase. 

Brassica rapa, a wild form of turnip, bok choy, and napa cabbage, in Mexico. Credit: Alex McAlvay
A wild form of turnip, bok choy, and napa cabbage, in Mexico. Credit: Alex McAlvay

The Convention on Biological Diversity (CBD), an agreement signed by 196 nations that the U.S. has yet to ratify, is attempting to clarify the rules governing global access to genetic resources, and what obligations, if any, there will be to acknowledge the contribution of Indigenous knowledge to commercial or scientific use of the plants. That includes demands for informed consent from Indigenous tribes for access to organisms in their territory, and some form of what’s come to be known as “access and benefit sharing” with those communities. Access by whom and what, precisely, is meant by “benefit,” were the subject of contentious negotiations at a CBD working group session in Nairobi in June.

An Access and Benefit Sharing fund was supposed to collect money from western companies and governments in return for their being able to access, research and utilize resources found on Indigenous lands, but there’s no requirement or enforcement mechanism and the amount of money deposited in the fund has thus far been minimal. A final set of globally affirmed guidelines is expected to be agreed upon at the CBD conference of the parties this December in Montreal.  

Eschewing Commercialization to Access Wild Genetics

Most botanical gardens claim to already be abiding by voluntary principles articulated by the Nagoya Protocol, an effort by the CBD to respond to concerns over bio-piracy. For the New York Garden and others, that means sharing whatever knowledge they generate with host country institutions, working closely with local scientific partners and agreeing not to apply the knowledge they gain for commercial purposes. McAlvay, for example, has been working closely with Ethiopian-based colleagues on the wild relatives of various legume varieties and with Republic of Georgia-based colleagues on wheat and barley relatives. This summer the garden is hosting an exhibit, Around the Table, celebrating the “art and science of edible plants,” highlighting the role of Indigenous knowledge and crop wild relatives in ensuring a diverse and resilient food system

wild apples illustration
Credit: Paul Horn

The Missouri Botanical Garden in St. Louis has sent several delegations to Kyrgyzstan, where they collaborate with the Kyrgyz government to research and collect samples of the wild apples that abound in the foothills of the Tian Shan mountain range straddling the frontier from Kyrgyzstan into China. As part of the deal, explained Rebecca Sucher, senior manager for collections at the garden and director of the apple expeditions, they’re working with the government  to devise breeding strategies to integrate some of the hardier apple relatives into the domesticated crop, and helping establish the country’s  own botanical garden in the capital of Bishkek.

Sucher picks up a softball-sized reddish-pink apple on her desk and held it up to her camera as we spoke on Zoom. She’d purchased it at a local market in St. Louis. “This apple is a Honeycrisp,” she says. “It shares a lot of the same genes as those tiny apples we worked with in the Tian Shan mountains in Kyrgyzstan …The genes in those apples can give it a longer shelf life, greater drought resistance than our domesticated apples. To not consider the value of these wild genetics as the climate changes would be terribly short sighted.”

Tony Gurnoe, director of conservation horticulture at San Diego Botanic Garden, surveying and collecting wild walnut in Lincoln National Forest, New Mexico. Credit: Tony Gurnoe

The garden’s agreement with Kyrgyzstan blocks any independent commercial application of the samples they obtained. The seed giant Monsanto may be headquartered in the same city—St. Louis—but no one from that company or any other, said Sucher, can gain access to the genetic characteristics contained in those native Kyrgyz apples for commercial purposes.

The reality, however, is that, in the absence of a global enforcement mechanism governing the use of genetic resources, controlling the flow of such materials is a challenge. There are considerable uncertainties as to how protected from commercial interests the growing collections actually are.

“There are multiple people involved in this chain of research around wild relatives,” said McAlvay. “On our end, we try to work ethically with our foreign partners.”

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That means cooperating with official government or tribal representatives to ensure that wild relative discoveries they help to unearth are ultimately applied to climate-resilient cultivation of domesticated crops in their centers of origin. In the U.S., that often means close cooperation with the USDA, which can deliver new insights into new breeding possibilities to farmers. Farmers might be able to cross-breed wild relatives with commercial crops, but agricultural corporations aren’t supposed to be able to turn them into proprietary products. 

But there’s no ironclad system to prevent corporate interests from accessing the varieties, separating out genes expressing desired characteristics and monopolizing  the result. As climate stresses accelerate, and wild relative characteristics become increasingly valuable, it will become more and more difficult to insulate their agricultural use on farms from commercial exploitation.

Without a global agreement, McAlvay said, “we may not have control over how the material [we find] is ultimately used.”

Eric Manyasa, left, a scientist focused on breeding dryland cereals with Benjamin Kilian of Crop Trust reviewing sorghum in Kakemega County, Kenya. Credit: Michael Major/Crop Trust
Eric Manyasa, left, a scientist focused on breeding dryland cereals with Benjamin Kilian of Crop Trust reviewing sorghum in Kakemega County, Kenya. Credit: Michael Major/Crop Trust

One of the most hotly debated questions at the Convention on Biological Diversity meeting this December will be how to put muscle and money toward ensuring that the genetic resources key to ensuring climate resilience aren’t locked up by corporate  interests. 

The potato is another subject of far-flung expeditions. In late May, Khoury set off from the San Diego Botanical Gardens for the Andes in search of the wild relatives of the Yukons, German Butterballs and Adirondack Blues in kitchens around the world. Those untamed cousins are generally gnarly, misshapen and bitter in comparison to the potatoes we’re accustomed to eating. But 26 of them were identified by the peer-reviewed journal Food and Energy Security as having multiple properties that could contribute, based on agro-ecological principles, to the adaptation of edible varieties facing significant climate shifts. The international team of plant scientists determined that those 26 varieties growing wild on the Andean hillsides—out of some 72 they monitored over multiple seasons—had the capacity to adapt to the rapid changes they were experiencing, “including tolerance to salinity, drought and temperature extremes.”

Any benefits found in the wild spuds, according to Khoury, will be shared with the Quechua, whose territorial home in the Andes is also the center of origin for the potato, which became a significant food source for non-Andean cultures after the British explorer Sir Walter Raleigh legendarily returned from his 16th-century colonial forays with samples of an Andean potato that took well to the moist, cool climate of Ireland. (The cultivation of just one potato variety there would infamously lead to an infestation by a single fungus that spread rapidly over uniform fields of the imported plant, leading to the potato famine that would transform Ireland and the United States in the mid-19th century).   

Closer to home, some gardens are seeking collaborations with members of Native American tribes, which had long experience and familiarity with growing food before European settlers transformed agriculture in North America. McAlvay, for example, has been working with the Shinnecock tribe in New York to expand the native plant section of the New York Botanical Garden in the Bronx to include many of the varieties integral to the tribe’s long-established home on eastern Long Island. He’s also collaborating with the tribe to document the traditional ecological knowledge they’ve used to sustain themselves.

Redefining the Difference Between Wild and Domestic

The botanic garden initiative is entwined with an overall move in the plant sciences to “decolonize botany.” Many of what are now considered “wild relatives” were in fact food sources for Indigenous communities for centuries before the arrival of Europeans. By the time colonists arrived, native communities across North America had been teasing out edible varieties of corn, squash, beans and multiple varieties of nuts from the vegetation growing wild in their territories, altering landscapes and moving plants to encourage or discourage their growth. There was little distinction between wild and domestic.

“We’ve been working with a very Euro-centric view of farming,” says McAlvay. “When the colonials got here [to North America], what the native people were doing didn’t look like English hedgerow agriculture.”

Yet, McAlvay points out, the Indigenous populations filled salt marshes to encourage the growth of certain edible roots, and transplanted others to locations more favorable for their growth.

“They were doing everything but planting and replanting domesticated plants,” he said.

But the colonists, and later anthropologists, didn’t see that as agriculture, and determined that native populations were “hunters and gatherers.”

“Their view was ‘This is farming, ‘That is not,’” McAlvay said. “And they didn’t see the agriculture all around them, or the complex societies that arose around it. Now we understand that these people took a very active role in working their land.”

Women threshing pearl millet in India. Credit: Shawn Landersz for Crop Trust
Women threshing pearl millet in India. Credit: Shawn Landersz/Crop Trust

The deep misunderstanding of native cultures that European settlers promulgated is, needless to say, embedded in the historical narrative of the last three centuries—and contributed to our own sense of what constitutes a “wild” versus a “domesticated” species. Botanic gardens may be coming late to appreciating their role in conserving these non-commercialized plants, but for many Indigenous cultures, the distinction between “domesticated” and “wild” is a false dichotomy. “Wild” presumes that there’s a world out there untouched by humans. But, as we’re learning, the ‘‘wilderness” is less wild than it appears to urban dwellers, and as the search for wild relatives demonstrates, there’s less distance between them and domesticated varieties than it may appear. Many wild relatives are yet to be discovered, and many will, no doubt, be found in what are now known and acknowledged to be in Indigenous lands.

“It was the displacement of Indigenous food relationships and Indigenous people that created the need now to seek out those wild relatives,” says Jesus Nazario, a member of the Nahuatl community in southern Mexico who is now studying Indigenous maize practices as a graduate student at the University of California, Berkeley. His family comes from southern Guerrero state, in the mountains north of Oaxaca, a center of corn biodiversity.

The name of the wild relative of corn—teosinte—is derived, according to Nazario,  from the Nahuatl words “teo” for sacred and “sincle,” for relative.

“We are all relatives of each other,” he said. 

A previous version of this story misidentified the journal in which Colin Khoury and his collaborators published their recent study on the wild relatives of food crops and misrepresented the number of wild crop seed extinctions between 1900 and 2015 as plant extinctions.

Mark Schapiro’s most recent book, SEEDS OF RESISTANCE: The Fight to Save Our Food Supply which chronicles the fight to control the seeds capable of resilience to climate change, will be published in paperback in October. His podcast, THE ELEMENTS, launches on public radio in the fall. He is also a lecturer at the University of California, Berkeley Graduate School of Journalism. Partial funding for this article was provided by Invoking the Pause.

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